The next morning I awoke feeling perfectly well. I thought a bathe
would do me good, and I went to plunge for a few minutes into the
waters of this mediterranean sea, for assuredly it better deserved
this name than any other sea.

I came back to breakfast with a good appetite. Hans was a good
caterer for our little household; he had water and fire at his
disposal, so that he was able to vary our bill of fare now and then.
For dessert he gave us a few cups of coffee, and never was coffee so
delicious.

"Now," said my uncle, "now is the time for high tide, and we must not
lose the opportunity to study this phenomenon."

"What! the tide!" I cried. "Can the influence of the sun and moon be
felt down here?"

"Why not? Are not all bodies subject throughout their mass to the
power of universal attraction? This mass of water cannot escape the
general law. And in spite of the heavy atmospheric pressure on the
surface, you will see it rise like the Atlantic itself."

At the same moment we reached the sand on the shore, and the waves
were by slow degrees encroaching on the shore.

"You may say so, uncle; but to me it is most extraordinary, and I can
hardly believe my eyes. Who would ever have imagined, under this
terrestrial crust, an ocean with ebbing and flowing tides, with winds
and storms?"

"Yes; with a westerly deviation of nineteen degrees forty-five
minutes, just as above ground. As for its dip, a curious fact is
coming to light, which I have observed carefully: that the needle,
instead of dipping towards the pole as in the northern hemisphere, on
the contrary, rises from it."

"Would you then conclude," I said, "that the magnetic pole is
somewhere between the surface of the globe and the point where we
are?"

"Exactly so; and it is likely enough that if we were to reach the
spot beneath the polar regions, about that seventy-first degree where
Sir James Ross has discovered the magnetic pole to be situated, we
should see the needle point straight up. Therefore that mysterious
centre of attraction is at no great depth."

I remarked: "It is so; and here is a fact which science has scarcely
suspected."

"Science, my lad, has been built upon many errors; but they are
errors which it was good to fall into, for they led to the truth."

"So," I said, examining the map, "the Highlands of Scotland are over
our heads, and the Grampians are raising their rugged summits above
us."

"Yes," answered the Professor laughing. "It is rather a heavy weight
to bear, but a solid arch spans over our heads. The great Architect
has built it of the best materials; and never could man have given it
so wide a stretch. What are the finest arches of bridges and the
arcades of cathedrals, compared with this far reaching vault, with a
radius of three leagues, beneath which a wide and tempest-tossed
ocean may flow at its ease?"

"Oh, I am not afraid that it will fall down upon my head. But now
what are your plans? Are you not thinking of returning to the surface
now?"

"Return! no, indeed! We will continue our journey, everything having
gone on well so far."

"Oh, I am not going to dive head foremost. But if all oceans are
properly speaking but lakes, since they are encompassed by land, of
course this internal sea will be surrounded by a coast of granite,
and on the opposite shores we shall find fresh passages opening."

"Oh, the trees were already down. Come, and you will see for
yourself."

After half an hour's walking, on the other side of the promontory
which formed the little natural harbour, I perceived Hans at work. In
a few more steps I was at his side. To my great surprise a
half-finished raft was already lying on the sand, made of a peculiar
kind of wood, and a great number of planks, straight and bent, and of
frames, were covering the ground, enough almost for a little fleet.

"It is fir, pine, or birch, and other northern coniferae, mineralised
by the action of the sea. It is called surturbrand, a variety of
brown coal or lignite, found chiefly in Iceland."

"But surely, then, like other fossil wood, it must be as hard as
stone, and cannot float?"

"Sometimes that may happen; some of these woods become true
anthracites; but others, such as this, have only gone through the
first stage of fossil transformation. Just look," added my uncle,
throwing into the sea one of those precious waifs.

The bit of wood, after disappearing, returned to the surface and
oscillated to and fro with the waves.

By next evening, thanks to the industry and skill of our guide, the
raft was made. It was ten feet by five; the planks of surturbrand,
braced strongly together with cords, presented an even surface, and
when launched this improvised vessel floated easily upon the waves of
the Liedenbrock Sea.